root@ubuntu:~# mdadm --assemble --scan mdadm: /dev/md/0 has been started with 3 drives (out of 4). root@ubuntu:~# vgchange -ay 5 logical volume(s) in volume group "vg_raid5" now active root@ubuntu:~# mount /dev/vg_raid5/lv_slash /mnt root@ubuntu:/mnt# fdisk -l Disk /dev/loop0: 1.8 GiB, 1905549312 bytes, 3721776 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop1: 87.9 MiB, 92123136 bytes, 179928 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop2: 140.9 MiB, 147722240 bytes, 288520 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop3: 2.3 MiB, 2355200 bytes, 4600 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop4: 13 MiB, 13619200 bytes, 26600 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop5: 14.5 MiB, 15208448 bytes, 29704 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop6: 3.7 MiB, 3878912 bytes, 7576 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/loop7: 42.1 MiB, 44183552 bytes, 86296 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/sda: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: gpt Disk identifier: 277579AF-D856-439C-9A67-6A4325FA0797 Device Start End Sectors Size Type /dev/sda1 2048 4095 2048 1M BIOS boot /dev/sda2 4096 5860532223 5860528128 2.7T Linux RAID Disk /dev/sdb: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: gpt Disk identifier: AF4BADA4-EE63-4CFD-AD01-B93DBB207EC9 Device Start End Sectors Size Type /dev/sdb1 2048 4095 2048 1M BIOS boot /dev/sdb2 4096 5860532223 5860528128 2.7T Linux RAID Disk /dev/sdc: 14.4 GiB, 15485370368 bytes, 30244864 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x15d9a6fb Device Boot Start End Sectors Size Id Type /dev/sdc1 * 2048 30244863 30242816 14.4G c W95 FAT32 (LBA) Disk /dev/sdd: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: gpt Disk identifier: 90BE1DA8-95C5-4583-8C35-9691D93F62E2 Device Start End Sectors Size Type /dev/sdd1 2048 4095 2048 1M BIOS boot /dev/sdd2 4096 5860532223 5860528128 2.7T Linux RAID Disk /dev/sde: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: gpt Disk identifier: 4F196F07-4B97-4012-A4EF-F9297386AD24 Device Start End Sectors Size Type /dev/sde1 2048 4095 2048 1M BIOS boot /dev/sde2 4096 5860532223 5860528128 2.7T Linux RAID Disk /dev/md0: 8.2 TiB, 9001368551424 bytes, 17580797952 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes Disk /dev/mapper/vg_raid5-lv_root: 28 GiB, 29997662208 bytes, 58589184 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes Disk /dev/mapper/vg_raid5-lv_swap: 18.6 GiB, 19998441472 bytes, 39059456 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes Disk /dev/mapper/vg_raid5-lv_var: 28 GiB, 29997662208 bytes, 58589184 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes Disk /dev/mapper/vg_raid5-lv_slash: 46.6 GiB, 49996103680 bytes, 97648640 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes Disk /dev/mapper/vg_raid5-lv_media: 8 TiB, 8796093022208 bytes, 17179869184 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes root@ubuntu:/mnt# mdadm --examine --scan && grep ARRAY /etc/mdadm/mdadm.conf ARRAY /dev/md/0 metadata=1.2 UUID=022134c7:f9c04632:1c36d157:4c71e634 name=groth:0 ARRAY /dev/md/0 metadata=1.2 UUID=022134c7:f9c04632:1c36d157:4c71e634 name=groth:0 root@ubuntu:/mnt# for i in /dev /dev/pts /proc /sys /run; do mount -B $i /mnt$i; done root@ubuntu:/mnt# chroot /mnt root@ubuntu:/# grub-install /dev/md0 Installing for i386-pc platform. grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install: error: unable to identify a filesystem in mduuid/022134c7f9c046321c36d1574c71e634; safety check can't be performed. root@ubuntu:/# grub-install /dev/md/0 Installing for i386-pc platform. grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install: error: unable to identify a filesystem in mduuid/022134c7f9c046321c36d1574c71e634; safety check can't be performed. root@ubuntu:/# grub-install /dev/sda Installing for i386-pc platform. grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. Installation finished. No error reported. root@ubuntu:/# update-grub2 Generating grub configuration file ... /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. Found background image: /usr/share/images/desktop-base/desktop-grub.png /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. Found linux image: /boot/vmlinuz-4.9.0-8-amd64 Found initrd image: /boot/initrd.img-4.9.0-8-amd64 /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. Found linux image: /boot/vmlinuz-4.9.0-6-amd64 Found initrd image: /boot/initrd.img-4.9.0-6-amd64 Found linux image: /boot/vmlinuz-4.9.0-3-amd64 Found initrd image: /boot/initrd.img-4.9.0-3-amd64 /usr/sbin/grub-probe: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. mkdir: cannot create directory ‘/var/lib/os-prober/mount’: No such file or directory mkdir: cannot create directory ‘/var/lib/os-prober/mount’: No such file or directory mkdir: cannot create directory ‘/var/lib/os-prober/mount’: No such file or directory mkdir: cannot create directory ‘/var/lib/os-prober/mount’: No such file or directory mkdir: cannot create directory ‘/var/lib/os-prober/mount’: No such file or directory Adding boot menu entry for EFI firmware configuration done root@ubuntu:/#